The present invention relates to a programme-controlled shutter capable of attaining the optimum exposure in response to the brightness of a subject.
There has been devised and demonstrated a programme-controlled shutter of the type consisting of shutter blades driven by a shutter mechanism and aperture setting blades or diaphragms driven by a servo-motor. In this shutter, the shutter blades and the aperture setting blades are controlled by two aperture control means so that the optimum exposure may be obtained by a suitable combination of an aperture and an exposure time. However, this shutter has a distinct defect that its mechanical construction is very complex because the shutter incorporates not only an aperture setting mechanism for setting an aperture but also a shutter mechanism for setting an exposure time.
The shutter mechanism utilizes the energy stored in a spring when the film is advanced so that it must incorporate means for storing the spring energy. Furthermore strong shock is encountered when the spring energy is transmitted to the shutter mechanism, causing the shaking of a camera with the result of blurring of a picture.